GRPFAN

I was at a gas pump today offering 110 octane on one of their pumps.

Anyone try this and how did your RX react?

MX5NES350

It wouldn't [react] so I would never bother.

hypervish

I wonder how my wallet would react? 110 octane must be friggin' expensive.

I assume the ECU would make adjustments for the octane, and everything would be fine.

kwbuggy

I think I have heard of people burning holes in their pistons from using aviation fuel (110 octane) but these might have been engines built before we got all these electronic ignition systems. I still wouldn't use it though.

burner22

Since it is a leaded fuel, it should do an efficient job at destroying your catalytic converters.

markrivers

110 octane, how much is that per gallon?
Currently, the 87 is 4.29 and the 91 is 4.49

MX5NES350

I it contains lead - which some do not - the cat and O2 sensors would go. If it doesn't then the fuel wouldn't burn anything than a hole in your wallet

MichaelPea

I once used 120 octane (AVGAS) in a Toyota Corona to see if it would run better. Of course the Corona predated all of the electronic octane sensors, etc. that we have today. Since we didn't have that, I had to tweak both side draft carburetors in order to get the car to start and run correctly but that was no big deal. And the car ran like a scalded dog.....for a while. Then, since I to lean out the air fuel mixture dramatically in order to run the car and (at that time) fuel vapors were part of the valve train cooling calculation, it proceeded to melt the valves. When I tore the engine down to see what happened, I was amazed at how much damage had been done and how quickly it was done. We're talking like 10 or 15 miles here....not hundreds. Long story made longer, I wouldn't try it in my RX or any other car that I wanted to keep for that matter.

JimH2

I would love to hear the Lexus response after you bring the RX in for repairs after using 110 octane.

MX5NES350

Thie higher octane wouldn't be an issue as long as it is unleaded. The knock sensors are meant for lower octane and pinging so the computer would take care of any timing issues. The real problem, as mentioned above, is whether this 110 octane is the leaded or unleaded version. Both are available on the market and the leaded version would be the one to cause eventual problems and the dealer even before Lexus would say you are on your own.

So maybe GRP can take another trip by the station and see if it is "regular" or "decaffeinated" fuel

MichaelPea

Aside from the obvious leaded vs. unleaded question, i'm wondering if modern octane sensors have upper and lower technical limits. I can imagine that there has to be some limit as manufacturing/engineering for infinite possibilities would be mighty expensive and impractical. Any technical experts out there?

JimH2

Based on the following article in addition to numerous other articles about higher octane racing fuels, it seems there is zero advantage in using such high octane fuels in the RX, which was designed for the 91-93 octane range for maximum efficiency and HP.

http://www.turborx7.com/fuel.htm

2011RX350

anything much over 93 octane is a waste of money. In a normally aspirated modern engine, it can only tweak the ignition so far, for a given compression ratio. By the same token, if you want to use 87 octane, go ahead and enjoy the savings. I have yet to use anything higher than 87 ocrane in mine and it does not ping. Will it make 275Hp on a 110F Summer day? No way. The engine management system with detweak the ignition and it might only make something like 250Hp. But most of the time, who cares? With regular unleaded at $3.439/gallon here, it feels good not to have to spend the extra $.20 to $.30+ for premium.

BTW, my AMEX Blue Cash Preferred card gives me a 3% cash rebate at gas stations so I actually paid ony $3.336 That might sound pretty good by the time this Summer rolls around... Average prices could really jump this year for the Memorial Day through labor day peak driving period.

MX5NES350

Thank you.